Tsunami/Transcript
Transcript Text reads: The Mysteries of Life with Tim and Moby Moby and Tim are sitting on a surfboard near a beach. They are looking for waves. Moby spots one. MOBY: Beep. TIM: Um, I don't think that's a good one. Moby paddles with his hands, trying to catch the wave. TIM: Moby, it's not-- The wave splashes over them. Tim is soaked. He frowns. A message in a bottle floats up to them. Tim retrieves and opens it. He reads from a typed letter. TIM: Dear Tim and Moby, Why do tsunamis happen? And what exactly are they? From, Pekka. Let's paddle in, OK? Moby paddles them back to shore. They stand on the beach. TIM: We've been hearing a lot about tsunamis lately. You probably know that they can cause a lot of damage and really devastate entire regions. So, let's try to understand how they happen. Some people call tsunamis tidal waves, but tsunamis have nothing to do with tides. MOBY: Beep. TIM: Well, the name tsunami is a combination of two Japanese words, tsu meaning harbor, and nami, meaning wave. So a tsunami is a harbor wave. Tsunamis happen when there's a violent disturbance deep below the ocean's surface, like an earthquake, landslide, or volcanic eruption. An image shows the earth from space. Images illustrate the disturbances as Tim names them. MOBY: Beep. TIM: Right. The underwater earthquakes in subduction zones are the most common cause of tsunamis. A world map shows location of subduction zones. TIM: When an oceanic plate hits a continental plate, the plates press together and pressure builds. Eventually, the heavier oceanic plate slips under the lighter continental one and causes an earthquake. Animations illustrate the interaction between continental and oceanic plates. TIM:The earthquake lifts part of the ocean floor up and drops other parts down. What happens on the ocean floor is mirrored on the surface of the water above. But gravity acts fast to even out the water's surface. An animation illustrates the disruption Tim describes. MOBY: Beep. TIM: Well, seismic energy created that big wave, and it doesn't just disappear. Even though the water looks flat, waves are rushing through it at speeds up to 970 kilometers per hour. Unlike the surface waves we're used to seeing, tsunami waves extend thousands of feet deep into the ocean. An animation illustrates enormous waves traveling beneath the ocean's flat surface. MOBY: Beep. TIM: Well, no. You don't see them. In fact, there can be hundreds of miles between the crests. Tsunami waves move a lot of water and carry a lot of energy, so they can travel long distances. An animation illustrates the size and power of the underground waves. MOBY: Beep. TIM: Like, sixteen-thousand kilometers long. When tsunami waves get close to shore, they don't have the room they need to keep moving along. An animation shows submerged tsunami waves reaching a shore. TIM: They slow down and pack together. The water swells, forming a wall of water with a whole lot of energy inside. An animation illustrates what Tim is describing. TIM: The water's force can plow through houses and level buildings. Depending on the shape of the ocean bottom, the wave can take different forms. Most often, a tsunami looks like a rapidly rising tide, flooding the shore at an alarming rate. An animation shows the onset of a tsunami wave. TIM: Some coastlines can slow the tsunami down enough to push it into a massive wave. An animation shows a huge wave rising and falling. TIM: Either way, the wave is carrying huge amounts of energy, and when all that water is unleashed on land, massive destruction follows. MOBY: Beep. TIM: Yeah, the natural world can be really harsh. It takes an earthquake with a Richter scale reading of more than 7.5 to generate a massive tsunami. But smaller earthquakes can generate tsunamis that still do a heck of a lot of damage! The one we saw in 2004 in the Indian Ocean was a Richter 9.0, so you can imagine the kind of damage that would do. Moby is standing next to Tim, holding their surfboard. MOBY: Beep. TIM: I know. It's kind of hard to wrap your head around that. MOBY: Beep. TIM: We don't have to if you don't want to. Moby looks reluctant. TIM: Well, how about I go out, and you spot for me? Moby nods. Tim gets on his surfboard, and Moby stands on the beach, pointing out waves. Tim rides by on a wave. Category:BrainPOP Transcripts Category:BrainPOP Science Transcripts